Effects of Submerged Vegetation Arrangement Patterns and Density on Flow Structure

Water, Journal Year: 2023, Volume and Issue: 15(1), P. 176 - 176

Published: Jan. 1, 2023

Aquatic vegetation appears very often in rivers and floodplains, which significantly affects the flow structure. In this study, experiments have been conducted to investigate effects of submerged arrangement patterns density on Deflected non-bending is arranged square staggered configurations channel bed a large-scale flume. Results showed that configuration leads intensified streamwise velocity, turbulence kinetic energy (TKE), Reynolds shear stress (RSS) compared configuration. When low (λ = 0.04 λ 0.07), produced wake rear more expansive than with high 0.09 0.17) because velocity center four elements lower middle two density. TKE zone deflected indicate maximum root-mean-square fluctuations occur at sheath section (z/H 0.1) top 0.4). behind elements, value RSS occurred slightly above interface between non-vegetation layer, showing Kelvin–Helmholtz instability associated inflectional points longitudinal velocity. Within range study (0.04 < ≈< 0.23), as increases, negative positive values throughout depth increase.

Language: Английский

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Characteristics of turbulent flow around bridge abutments in the presence of vegetation in channel bed under ice-covered flow conditions

Cold Regions Science and Technology, Journal Year: 2024, Volume and Issue: 221, P. 104172 - 104172

Published: March 11, 2024

During winter, ice cover frequently forms on the water surface of rivers with vegetated channel beds in cold regions. The investigation impacts both and bed vegetation flow structures around bridge abutments is essential for engineers to gain a comprehensive understanding complex interactions occurring such situation. In present study, structure rectangular abutment presence under ice-covered conditions has been studied. Considering different densities by arranging elements square staggered configurations, this study incorporates influence covers roughness, namely smooth rough cover. Key turbulence parameters, including intensity, Reynolds shear stress (RSS), turbulent kinetic energy (TKE), are also examined based laboratory experiments. Results show that shape velocity profiles over changes from an S-shaped curve open condition convex conditions. effects create unpredictable intensity patterns. Under rough-covered condition, there appears larger area negative (RSS) downstream abutment. Turbulent (TKE) substantially lower magnitudes than

Language: Английский

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Turbulent flow characteristics over gravel bed channel with submerged vegetation patches

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(3)

Published: March 1, 2025

This experimental research investigates the turbulent flow dynamics in a narrow open channel with submerged finite uniform patches of flexible and rigid vegetation placed along sides at equal intervals. A Sontek FlowTracker 2.0 Acoustic Doppler Velocimeter was used to collect instantaneous velocity data evaluate essential attributes, including profiles, Reynolds shear stress, higher-order moments, bursting events. The findings indicate that maximum intensity turbulence occurs inflection point immediately above plant's canopy. Vegetation greatly affects structure, reducing zone increasing Compared upstream non-vegetation zone, depth-averaged increased by 24% canopy, diminished 19% below 12% downstream non-vegetated vegetation. For patches, 23% 25% 5% as compared zone. Quadrant analysis revealed occurrence sweeps ejections more nearer vegetated bed. Furthermore, arrangement placement were pivotal diminishing affecting momentum transfers between zones. These significantly modifies patterns, dispersing loads. enhances comprehension flow-vegetation natural channels, impacting riverbank stability ecological habitat management.

Language: Английский

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Quantitative Analysis of the Seasonal Growth of Myricaria laxiflora on Flow Structure

Ecohydrology, Journal Year: 2025, Volume and Issue: 18(3)

Published: April 28, 2025

ABSTRACT Previous studies on vegetation–flow interactions have underestimated the morpho‐biomechanical complexity of riparian plants. By integrating mechanical testing and flume experiments, study deciphered morpho‐mechanical adaptations Myricaria laxiflora (a Three Gorges shrub) across its dormant period, early growth boom while analysing flow structure responses in wake area. Biomechanically, stem stiffness showed minimal variation between periods, but bending modulus increased twelvefold during period. Aquatic morphological changes were jointly determined by frontal area properties: Under maximum rates, greatest occurred followed period then From to vertical expansion zone shifted from regions distal bed areas adjacent bed, causing a corresponding descent velocity inflection points within downstream mean profiles. During development small leaves lateral branches enhanced area, elevated rates triggered vegetation reconfiguration, thereby weakening overall resistance. Turbulence analysis revealed spatially expanded sweep dominance intensified ejections vortices at shear boundary layers vegetation, amplified inward/outward linked branch growth, dense leaf morphology promoting turbulence dissipation, flexible stems homogenising stabilising vortical structures.

Language: Английский

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Effect of submerged vegetation on hydraulic resistance of ice-covered flows

International Journal of Sediment Research, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 1, 2024

Language: Английский

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Simulation of Accelerated Subcritical Flow Profiles in an Open Channel with Emergent Rigid Vegetation

Applied Sciences, Journal Year: 2022, Volume and Issue: 12(14), P. 6960 - 6960

Published: July 9, 2022

Even though both fluid mechanics and numerical studies have considerably progressed in the past decades, experimental knowledge remains an important tool for studying resistance to flow media where a complex environment dominates pattern. After comprehensive review of recent literature on drag coefficient open channels with emergent rigid vegetation, this paper presents results related 29 accelerated subcritical profiles (i.e., M2 type) that were observed flume experiments stems square arrangement at University Calabria (Italy). First all, we used some formulas coefficient, concluding they unsatisfactory, probably because their derivation uniform or quasi-uniform conditions. Then, tested recently proposed approach, but when plotted versus stem Reynolds number, calculated coefficients showed inconclusive behavior interpret. Thus, new approach considers calibration Manning simulation free surface profile, then evaluation based fundamental equations. With help classical dimensional analysis, regression equation was found estimate by means non-dimensional parameters, which include vegetation density, number computed using depth as characteristic length. This simulate all 26 and, also, 4 profiles, good. The could be squared arrangements, within range densities, numbers present study. However, case three authors staggered arrangement, gives significantly underestimated depths.

Language: Английский

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Drag Coefficient of Submerged Flexible Vegetation Patches in Gravel Bed Rivers

Water, Journal Year: 2022, Volume and Issue: 14(5), P. 743 - 743

Published: Feb. 25, 2022

Vegetation patches and strips either along riverbanks or in channel beds are essential for the protection of erosion sedimentation processes. In present study, drag coefficient Cdv submerged flexible vegetation gravel bed rivers was investigated. A total 13 with different densities were studied disparate reaches Padena Marbor Beheshtabad Iran. Water depths, flow velocities, particle grain sizes around these collected. The Saint-Venant equation various empirical equations estimating applied to study hydrodynamics presence under nonuniform conditions. Furthermore, factor used represent flexibility characteristics, which explored from perspective material mechanics. results showed that calculated values exhibited variations increase Reynolds number streamwise direction due nonuniformity. Two effects caused by observed, namely, sheltering effect (for Red>580) blockage Red<450). most vegetated patches, dominant, reduced coefficient. Finally, a fitting formula proposed based on Cauchy number.

Language: Английский

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Comparison of Velocity and Reynolds Stress Distributions in a Straight Rectangular Channel with Submerged and Emergent Vegetation

Water, Journal Year: 2023, Volume and Issue: 15(13), P. 2435 - 2435

Published: July 1, 2023

Vegetation in rivers and streams plays an important role preventing erosion improving bank stability. Comparison between emergent vegetation (bank vegetation) submerged vegetation, terms of velocity Reynolds stress distributions, for the same aspect ratio flow discharge, has received limited attention literature. This study investigates stress, as well log law a laboratory flume compares results different set up with sediment size but discharge. The indicate that influence on secondary currents generation is less than vegetation. In addition, application valid both cases, however, it to y/h = 0.75 (in which cover banks partly out water) 0.25 bank. For distribution presents convex form turning point. those artificial pool over low (<5) keeps almost distributions decreases point distribution. cover, location zero shear superposes maximum velocity, approaching shifting towards bed, approaches bed.

Language: Английский

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Flow turbulence presented by different vegetation spacing sizes within a submerged vegetation patch

Journal of Hydrodynamics, Journal Year: 2023, Volume and Issue: 35(6), P. 1131 - 1145

Published: Dec. 1, 2023

Language: Английский

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Remote Sensing of Ecohydrological, Ecohydraulic, and Ecohydrodynamic Phenomena in Vegetated Waterways: The Role of Leaf Area Index (LAI)

Published: May 1, 2021

Aquatic plants have considerable effects on the hydraulic roughness and qualitative status of vegetated flows at real scale. Defining most suitable practice riparian vegetation control in manmade natural water represents a key point, both environmental river engineering, particularly considering ongoing climate change trends. In detail, elements modify main fluid dynamic features, with impacts transport pollutants mixing traits across flows. This study was carried out to provide deep knowledge ecohydrodynamic synergy between flow field scale, within ditch covered by rigid plants. It possible, assessing accuracy drone-based imagery computing Leaf Area Index (LAI), further calibrate predictive models vegetative resistance.

Language: Английский

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